Half Life One was one of the most revolutionary games of its times. In many ways, it reinvented gaming. Black Mesa Source is the same game redone completely with new graphics. Do not confuse this with Half Life Source released by Valve Software. Half Life Source was just a slightly updated game. Black Mesa Source is completely redone and its free for everyone. So get it on Steam. Just sign up for the free account, download the game and Source 2007 from to play it.